Configuring Cisco ASA 5505 for another IP address range

We have a working connection to our ASA from our ISP, and we have it configured with an address range of:

Public LAN: xxx.xxx.xxx.xxx/28

Subnet Mask: 255.255.255.240

on the outside interface. We asked our ISP for another block of IPs, and they gave us another range of IPs:

Public LAN: yyy.yyy.yyy.yyy/28

Subnet Mask: 255.255.255.240

How can I add this new set of IPs to the outside interface on the Cisco ASA 5505?

From serverfault

• You just need to add them with the secondary switch i.e. from inside of the interface config

  (config-if)#ip address yyyy.yyyy.yyyy.yyyy 255.255.255.240 secondary
  

  : Trent, thanks, but we had to add a route on our gateway device, a router that was in front of the ASA. This was preventing the traffic from getting to the ASA. We routed all traffic to one of the working xxx.xxx.xxx.xxx addresses. I'm sure your answer would have worked, but I answered also in case someone else has my problem.
  From trent

• We had to add a route on our gateway device, a router that was in front of the ASA. This was preventing the traffic from getting to the ASA. We routed all traffic to one of the working xxx.xxx.xxx.xxx addresses.

  From